Wood smoke particles from different combustion phases induce similar pro-inflammatory effects in a co-culture of monocyte and pneumocyte cell lines.

BACKGROUND: Exposure to particulate matter (PM) has been linked to several adverse cardiopulmonary effects, probably via biological mechanisms involving inflammation. The pro-inflammatory potential of PM depends on the particles' physical and chemical characteristics, which again depend on the emitting source. Wood combustion is a major source of ambient air pollution in Northern countries during the winter season. The overall aim of this study was therefore to investigate cellular responses to wood smoke particles (WSPs) collected from different phases of the combustion cycle, and from combustion at different temperatures. RESULTS: WSPs from different phases of the combustion cycle induced very similar effects on pro-inflammatory mediator release, cytotoxicity and cell number, whereas WSPs from medium-temperature combustion were more cytotoxic than WSPs from high-temperature incomplete combustion. Furthermore, comparisons of effects induced by native WSPs with the corresponding organic extracts and washed particles revealed that the organic fraction was the most important determinant for the WSP-induced effects. However, the responses induced by the organic fraction could generally not be linked to the content of the measured polycyclic aromatic hydrocarbons (PAHs), suggesting that also other organic compounds were involved. CONCLUSION: The toxicity of WSPs seems to a large extent to be determined by stove type and combustion conditions, rather than the phase of the combustion cycle. Notably, this toxicity seems to strongly depend on the organic fraction, and it is probably associated with organic components other than the commonly measured unsubstituted PAHs.

Meeting report: national workshops for the communication of air pollution and health information: summary of four workshops in different regions of Europe.

AIRNET was a thematic network project (2002-2004) initiated to stimulate the interaction between researchers in air pollution and health in Europe. As part of AIRNET's communication strategy, a standardized workshop model was developed to organize national meetings on air pollution and health (AIRNET network days) . Emphasis was given to tailor the national workshop information and related activities to the specific needs of a wider range of stakeholders (e.g., policy makers, nongovernmental organizations, industry representatives) . In this report we present an overview of the results of four workshops held in western, northern, central/eastern, and southern regions of Europe in 2004. Overall, workshop experiences indicated that by actively involving participants in the planning of each meeting, AIRNET helped create an event that addressed participants' needs and interests. A wide range of communication formats used to discuss air pollution and health also helped stimulate active interaction among participants. Overall, the national workshops held by AIRNET offered a way to improve communication among the different stakeholders. Because a broad stakeholder involvement in decision making can positively affect the development of widely supported policies, such meetings should be continued for Europe and elsewhere.

Stakeholder needs for air pollution and health information.

Within the European Commission-supported thematic network project AIRNET, a stakeholder survey was performed to identify key questions and issues of concern for end users regarding air pollution and health information. On the whole, survey respondents typically asked general questions concerning air pollution and health (i.e., regarding the type of pollutant, emission sources, monitoring, and health impact). Furthermore, an overwhelming response across all stakeholder categories was not the unavailability of information sources to inform policy, but the lack of time available to read and absorb all the information. Overall, the respondents expressed their preference for information that is (1) presented as short and clear overviews, (2) ready for policy use by including a practical linkage between the research findings and implementation of public protection, and (3) in a format easily passed on to others.

Differential effects of the particle core and organic extract of diesel exhaust particles.

Exposure to diesel engine exhaust particles (DEPs), representing a complex and variable mixture of components, has been associated with lung disease and induction of pro-inflammatory mediators and CYP1A1 expression. The aim of this study was to further characterise DEP-components accounting for these effects. Human bronchial epithelial cells (BEAS-2B) were exposed to either native DEPs, or corresponding methanol DEP-extract or residual DEPs, and investigated with respect to cytotoxicity and expression and release of multiple inflammation-related mediators. Both native DEPs and DEP-extract, but not residual DEPs, induced marked mRNA expression of COX-2, IL-6 and IL-8, as well as cytotoxicity and release of IL-6. However, CYP1A1 was primarily induced by the native and residual DEPs. Overall, the results of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and gas chromatography with mass spectrometry (GC/MS) analysis of DEP-extracts indicated that the majority of the analysed PAHs and PAH-derivatives were extracted from the particles, but that certain PAH-derivatives, probably their carboxylic isomers, tended to be retained on the residual DEPs. Moreover, it appeared that certain components of the methanol extract may suppress CYP1A1 expression. These results provide insight into how different components of the complex DEP-mixture may be differently involved in DEP-induced pro-inflammatory responses and underscore the importance of identifying and clarifying the roles of active DEP-components in relation to different biological effects.